Re: explicit dcache <-> user-space cache coherency, sys_mark_dir_clean(), O_CLEAN

Linus Torvalds
2004-02-20T17:15:00Z

On Fri, 20 Feb 2004, Ingo Molnar wrote:
>
> there's another class of problems: is it an issue that directory renames
> that move this directory (higher up in the directory hierarchy of this
> directory) do not invalidate the cache? In that case there's no dnotify
> event either.

This is one of the reasons why I worry about user-space caching. It's just
damn hard to get right.

It's hard in kernel space too, of course, but we've had smart people
working on the dcache for years. So if we can sanely avoid duplication,
that would be a good thing.

Linus